By Dr. Jarrod Sadulski | 08/24/2026
The Fourth Amendment of the U.S. Constitution guarantees protection from unreasonable searches and seizures by law enforcement officers and sets limits on their power. These protections guide everyday law enforcement actions.
Every time evidence is seized in a crime, a law enforcement officer must enter a place where a citizen has a reasonable expectation of privacy. Whenever an officer conducts a search, the Constitution’s Fourth Amendment must be considered. Otherwise, serious repercussions may occur if an officer does not properly apply the Fourth Amendment to their daily activities.
How Exigent Circumstances Affect Fourth Amendment Searches
The Fourth Amendment applies to nearly any police investigation where a person or property is going to be searched. In addition, it applies to the court officials who issue search warrants.
In addition, probable cause is required for police officers to obtain a search warrant, under the terms of the Fourth Amendment. Probable cause means that a reasonable person would suspect that a crime has been committed or that evidence of a crime exists at a particular location.
Over time, however, case laws have been established in terms of:
- When a search warrant is required
- When law enforcement may act without a search warrant, such as exigent circumstances
Exigent circumstances apply when officers are permitted to mitigate an imminent danger or prevent evidence from being destroyed.
Case laws that guide law enforcement on how to apply the Fourth Amendment date back many decades. For instance, the 1967 ruling in Warden v. Hayden established the legal doctrine that permits officers to enter a residence without a warrant while in hot pursuit of a suspect.
How the Fourth Amendment Applies to Digital Technology
Technology and the online world have introduced a lot of ambiguity regarding how the Fourth Amendment should be applied today. The digital world was not considered when the Fourth Amendment was written. However, the amendment still protects personal information for which someone has a reasonable expectation of privacy.
Since the application of the Fourth Amendment in the digital age is relatively new, it is crucial to determine:
- What is considered public information online
- What is considered private online information protected by the Fourth Amendment
The standard for an expectation of privacy can be blurry, especially in the digital sense. An example is social media.
Does someone have a right to privacy from government intrusion and the interception of what is posted on social media? It depends.
Content posted on social media platforms – such as pictures, messages, and profile information – that can be viewed by the public typically falls under the plain view doctrine. As a result, there is no expectation of privacy.
For example, if someone posts threats or other illegal content on social media and that person’s social media profile is set to public in the digital world, then law enforcement could potentially use that content as evidence without a search warrant. If that same online content is restricted through privacy settings, then a search warrant would be needed to seize that evidence.
Digital Evidence, Fourth Amendment Privacy Rights, and the Online World
A lot of crime in the online world is communicated via private messages. These private messages include:
- Private messages sent via social media sites
- Telegram® messages
- WhatsApp® messages (typically encrypted)
- Signal® messages (typically encrypted)
These private messages are typically regarded like emails or cell phone texts, which may require a search warrant according to U.S. Constitution principles.
Certain information transmitted online has reduced privacy protections, and case law is needed to guide law enforcement on when the Fourth Amendment is applicable.
Some traditional Supreme Court rulings can be applied to privacy and searches in the digital age. For example, the 1967 landmark Supreme Court case Katz v. United States established the “reasonable expectation of privacy” test that can be applied to computers. If someone sends a private message with the intent for it to only be read by the intended recipient, then a search warrant would typically be needed to access the content.
Much of our personal information is contained in our cell phones. The 2014 Riley v. California case established that texts, emails, and personal messages stored in a cell phone are protected from government intrusion without a search warrant.
The Impact of AI Technology and the Fourth Amendment
The advancement of artificial intelligence (AI) will likely test boundaries against government searches and seizures in regard to the Fourth Amendment. Artificial intelligence may be used in mass surveillance on the internet and in facial recognition.
Artificial intelligence can be used to enhance investigative capabilities by predicting behaviors and movements. AI is also helpful in combing through large datasets to compile information about a particular person.
But there are questions regarding whether artificial intelligence’s algorithms can be used to develop probable cause to conduct a search or an arrest. In the future, clear guidelines set through case laws will be needed to provide boundaries and safeguards for how AI can be used by law enforcement.
The Bachelor of Arts in Criminal Justice at APU
For learners interested in studying criminal justice, American Public University (APU) provides an online Bachelor of Arts in Criminal Justice. This degree offers courses in U.S. law enforcement, criminal law, and the criminal legal process. Other courses include criminology, ethics in criminal justice, and constitutional law.
In addition, this B.A. in criminal justice offers four concentrations so that students can tailor their education according to their professional goals:
- Entrepreneurship
- General
- Maritime law enforcement
- Organizational law enforcement leadership
For more information about this B.A. in criminal justice, visit APU’s security and global studies degree program page.
Note: This degree program is not designed to meet the educational requirements for professional licensure or certification in any country, state, province, or other jurisdiction. This program has not been approved by any state professional licensing body and does not lead to any state-issued professional licensure.
Telegram is a registered trademark of Telegram FZ-LLC.
WhatsApp is a registered trademark of WhatsApp, LLC.
Signal is a registered trademark of Signal Technology Foundation.
Dr. Jarrod Sadulski is an associate professor in the School of Security and Global Studies and has over 20 years in the field of criminal justice. He holds a bachelor’s degree in criminal justice from Thomas Edison State College, a master’s degree in criminal justice from American Military University, and a Ph.D. in criminal justice from Northcentral University.
His expertise includes training on countering human trafficking, maritime security, mitigating organized crime, and narcotics trafficking trends in Latin America. Jarrod has also testified to both the U.S. Congress and U.S. Senate on human trafficking and child exploitation. He has been recognized by the U.S. Senate as an expert in human trafficking.
Jarrod frequently conducts in-country research and consultant work in Central and South America on human trafficking and current trends in narcotics trafficking. Also, he has a background in business development.